Change hash table to use linear probing and add unit test.

CMakeLists.txt

Makefile

build.yaml

src/core/lib/slice/slice_hash_table.c

src/core/lib/slice/slice_hash_table.h

test/core/slice/BUILD

test/core/slice/slice_hash_table_test.c

tools/run_tests/generated/sources_and_headers.json

tools/run_tests/generated/tests.json

vsprojects/buildtests_c.sln

.../test/slice_hash_table_test/slice_hash_table_test.vcxproj

...ice_hash_table_test/slice_hash_table_test.vcxproj.filters