Add testdata files for quantized stablohlo programs

[sdasgup3]

Add quantized tests for the following stablehlo operations

abs
cbrt
ceil
cosine
divide
exponential
exponential_minus_one
floor
log
log_plus_one
logistic
multiply
negate
sign
sine
sqrt
subtract
tanh

A few details

• These tests are all auto-generated by a testdata-generator tool which takes an input a non-quantized program file from https://github.com/openxla/stablehlo/tree/main/stablehlo/tests/interpret or https://github.com/openxla/stablehlo/tree/main/stablehlo/testdata and generates a quantized program file in the same format as the input file.
• The test file names have 1-1- correspondence with its input file name appended with _qi8 appended, suggesting that all the quantized program involves i8 as storage type.
• The constant argument fed to each test file is the same as that fed to the input program.

A few limitations

1. Currently we are using the Stablehlo Quantizer to generate quantized program which currently supports quantization of f32 floating point programs only. In future this case be improved.
   • Corollary: If the input test files have non-f32 based pograms, then it will be preserved unquantized in the output file. That is why we can see some of the generated files have non-quantized programs as well.
2. While scraping the input programs from https://github.com/openxla/stablehlo/tree/main/stablehlo/tests/interpret or https://github.com/openxla/stablehlo/tree/main/stablehlo/testdata we choose only those programs which tests single stablehlo operations. This what the testdata-generator tool currently supports, but in very near future we can expect the tool to work on input test files with mutiple operations being tested.

Keep an eye on more quantized tests to be populated!