TBR: i#1686 decoder testing: add api.disA32 and api.disT32 binary decoding tests

Commit log for first patchset:
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i#1686 decoder testing: add api.disA32 and api.disT32 binary decoding tests

Adds a new helper app api.dis-create which takes a large random binary and
pulls out a subset of it that contains the head of the file and then caps
the count of each opcode in order to create a manageable pre-commit-suite
test.  It also appends a few hardcoded entries for rare opcodes to ensure
coverage.

Adds two new tests, api.disA32 and api.disT32, which use the result of the
api.dis-create helper and disassemble their own input binaries.  The
expected output for now is the DR format (already compared for register
usage with Capstone).  Eventually we want to finish -syntax_arm and use
that as the format to check all the operands as well.

Splits up the tobuild_api() routine to support this.
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[bruening, 2015-04-18 00:43:50]

Committed as
https://github.com/DynamoRIO/dynamorio/commit/1faa08248d1528cd1f3839e6e6cde33...

Final commit log: 
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i#1686 decoder testing: add api.disA32 and api.disT32 binary decoding tests

Adds a new helper app api.dis-create which takes a large random binary and
pulls out a subset of it that contains the head of the file and then caps
the count of each opcode in order to create a manageable pre-commit-suite
test.  It also appends a few hardcoded entries for rare opcodes to ensure
coverage.

Adds two new tests, api.disA32 and api.disT32, which use the result of the
api.dis-create helper and disassemble their own input binaries.  The
expected output for now is the DR format (already compared for register
usage with Capstone).  Eventually we want to finish -syntax_arm and use
that as the format to check all the operands as well.

Splits up the tobuild_api() routine to support this.

Review-URL: https://codereview.appspot.com/231760044
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