Create String.replace SIMD function

[zacky1972]

I guess to implement String.replace/4 using SIMD instructions will be as follows:

1. Allocate a memory area for replaced string because memory area in Elixir should be immutable.
   • Keep the same size to the original memory area if the length of the pattern is larger than that of the replacement.
   • Otherwise, keep some larger size than the original memory area.
2. Copy the original memory area into the replaced string memory area until the pattern is matched to the original memory area or the end of the area is reached, with auto-vectorization and SIMD instructions.
3. Copy the rest of the original area into the replaced area if the length of the rest is smaller than the pattern with auto-vectorization and SIMD instructions, and Finish.
4. Match the whole of the pattern and the original area with auto-vectorization and SIMD instructions
   • If matched, confirm and reallocate if necessary the size of the rest of the replaced string area to have an enough capacity, and copy the replacement into the replaced string area with auto-vectorization and SIMD instructions.
   • If not, copy the unmatched original area into the replaced string area with auto-vectorization and SIMD instructions.
5. Go back 2

This issue is a part of #49

branch name is string_replace.

[zacky1972]

MacBook Air

StringReplaceBench

benchmark name iterations average time StringReplace.replace 10000000 0.35 µs/op String.replace 1000000 1.26 µs/op

SIMD version is 3.6x faster than original String.replace!!!

[zacky1972]

iMac Pro

## StringReplaceBench
benchmark name         iterations   average time 
StringReplace.replace    10000000   0.20 µs/op
String.replace           10000000   0.67 µs/op

3.35x faster!

[piacerex]

Windows 10 (Intel CORE m3: 2 Pysical cores / 4 Logical cores)

## LogisticMapBench
benchmark name          iterations   average time
Pelemay                       1000   1438.00 ﾂｵs/op
Enum                           500   4626.00 ﾂｵs/op
Flow                           200   7890.00 ﾂｵs/op
## StringReplaceBench
benchmark name          iterations   average time
Pelemay String.replace     1000000   1.58 ﾂｵs/op
Enum String.replace         500000   4.62 ﾂｵs/op
Flow String.replace           5000   662.40 ﾂｵs/op

2.92x faster (This was close to mac result)

I'll try data preprocessing with Esuna using Pelemay :-)