Update resolver.ts to prevent crashing when encountering WASM modules

[pvh]

Not sure if this is a great approach but it appears to work in my narrow use-case whereas before I got a crash that looked thus:

file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:1800
                throw new JspmError(`${errStack}\n\nError parsing ${resolvedUrl}:${pos}`);
                      ^
JspmError: 
  asm����>`````~`|```~```~`````````     `       `
> `
   ```` ~~~`~`~~`|`~`~`|`|`||`~`~`~`~~`~|`}`|`|`|`~`~`~`~`~`~`~~`~~~~`}`|`|`~`~`~~~`|`||����V./automerge_wasm_bg.js__wbindgen_object_drop_ref./automerge_wasm_bg.js__wbindgen_error_new./automerge_wasm_bg.js__wbindgen_string_get./automerge_wasm_bg.js__wbg_new_abda76e883ba8a5f./automerge_wasm_bg.js__wbg_stack_658279fe44541cf6./automerge_wasm_bg.js__wbg_error_f851667af71bcfc6./automerge_wasm_bg.js__wbindgen_is_object./automerge_wasm_bg.js__wbindgen_jsval_loose_eq./automerge_wasm_bg.js__wbg_String_91fba7ded13ba54c./automerge_wasm_bg.js__wbindgen_bigint_from_i649./automerge_wasm_bg.js__wbindgen_bigint_from_u649./automerge_wasm_bg.js__wbg_set_20cbc34131e76824    ./automerge_wasm_bg.js&__wbg_getRandomValues_37fa2ca9e4e07fab./automerge_wasm_bg.js%__wbg_randomFillSync_dc1e9a60c158336d./automerge_wasm_bg.js__wbg_crypto_c48a774b022d20ac./automerge_wasm_bg.js__wbg_process_298734cf255a885d./automerge_wasm_bg.js__wbg_versions_e2e78e134e3e5d01./automerge_wasm_bg.js__wbg_log_1d3ae0273d8f4f8a./automerge_wasm_bg.js__wbg_log_576ca876af0d4a77./automerge_wasm_bg.js__wbg_get_44be0491f933a435./automerge_wasm_bg.js__wbg_length_fff51ee6522a1a18./automerge_wasm_bg.js__wbg_new_898a68150f225f2e./automerge_wasm_bg.js __wbg_newnoargs_581967eacc0e2604./automerge_wasm_bg.js__wbg_get_97b561fb56f034b5./automerge_wasm_bg.js__wbg_new_b51585de1b234aff./automerge_wasm_bg.js__wbg_length_b3de0c6587c18245./automerge_wasm_bg.js__wbg_set_502d29070ea18557    ./automerge_wasm_bg.js__wbg_new_d258248ed531ff54./automerge_wasm_bg.js__wbg_new_cd59bfc8881f487b./automerge_wasm_bg.js(__wbg_instanceof_Object_3daa8298c86298be./automerge_wasm_bg.js__wbg_assign_999478a110912e87./automerge_wasm_bg.js%__wbg_defineProperty_2db1bcb00cd9da96

Error parsing https://ga.jspm.io/npm:@automerge/automerge-wasm@0.2.6/bundler/automerge_wasm_bg.wasm:2:3155
    at Resolver.analyze (file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:1800:23)
    at async file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2953:85
    at async TraceMap.getTraceEntry (file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2965:9)
    at async TraceMap.visit (file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2710:23)
    at async file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2743:13
    at async Promise.all (index 0)
    at async TraceMap.visit (file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2738:9)
    at async file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2743:13
    at async Promise.all (index 0)
    at async TraceMap.visit (file:///Users/pvh/Dev/blutack/node_modules/@jspm/generator/dist/generator-49949c79.js:2738:9) {
  jspmError: true,
  code: undefined
}

As far as I can tell WASM modules can't have any dependencies so I think this is correct? Let me know if I can provide any more information.

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[pvh]

I'm not much familiar with deno but I don't think I've changed anything that relates to this failing test. Happy to look into it if you think it's something I've done.