Fix remote tests to work on RBE

### Fixed tests
- [x] //src/tools/singlejar:zip64_test.
Fix https://github.com/bazelbuild/bazel/pull/8034
- [x] //src/tools/singlejar:combiners_test.
OOMs because it requires > 5GiB memory. Fix is to use a high mem worker.
- [x] //src/test/shell/integration:discard_analysis_cache_test
Fix https://github.com/bazelbuild/bazel/pull/8036
- [x] //src/test/shell/integration:discard_graph_edges_test
Fix https://github.com/bazelbuild/bazel/pull/8037
- [x] //src/test/shell/integration:nonincremental_builds_test
Fix https://github.com/bazelbuild/bazel/pull/8038
- [x] //src/test/shell/bazel:bazel_example_test
Fix https://github.com/bazelbuild/bazel/pull/8041
- [x] //src/test/shell/bazel:bazel_with_jdk_test
Fix https://github.com/bazelbuild/bazel/pull/8042
- [x] //src/test/py/bazel:launcher_test, //src/test/py/bazel:py_test, , //src/test/py/bazel:runfiles_test, //src/test/py/bazel:bazel_external_repository_test
Auto-Configuration Error: Cannot find gcc or CC; either correct your path or set the CC environment variable
- [x] //src/test/py/bazel:runfiles_sandboxed_test, //src/test/py/bazel:cc_import_test, //src/test/py/bazel:runfiles_test
- [x] //src/test/py/bazel:bazel_external_repository_test
ImportError: No module named six.moves
- [x] //src/test/shell/bazel:embedded_tools_deps_test
- [x] //src/test/shell/bazel:bazel_coverage_cc_test_gcc
- [x] //src/test/shell/bazel:bazel_coverage_sh_test
- [x] //src/test/shell/bazel:bazel_cc_code_coverage_test
Missing lcov on docker image. Will be included in next release.
- [x] //src/test/shell/bazel:bazel_coverage_java_test
https://github.com/bazelbuild/bazel/issues/6450
- [x] //src/test/shell/bazel:bazel_sandboxing_cpp_test
Fix https://github.com/bazelbuild/bazel/pull/8046
- [x] [ ] //src/test/java/com/google/devtools/build/android/...
- [x] //tools/android/...
- [x] //scripts/...

### Yet to fix
- [ ] //src/tools/singlejar:output_jar_simple_test
Fix this to work with absolute paths
```
copts = select({
"//src/conditions:windows": ["-DJAR_TOOL_PATH=\\\"io_bazel/$(JAVABASE)/bin/jar.exe\\\""],
"//conditions:default": ["-DJAR_TOOL_PATH=\\\"io_bazel/$(JAVABASE)/bin/jar\\\""],
}),
```
- [ ] //src/test/shell/bazel:external_integration_test
- [ ] //src/test/shell/bazel:maven_test
- [ ] //src/test/shell/bazel:bazel_repository_cache_test
- [ ] //src/test/shell/integration:java_integration_test
- [ ] //src/test/java/com/google/devtools/build/lib:sandbox-tests
- [ ] //src/test/shell/bazel/android/...
@jin is working on a fix https://github.com/bazelbuild/bazel/issues/8235

Start with the remaining test targets listed in the issue, especially src/tools/singlejar:output_jar_simple_test and its absolute-path configuration, then review the external_integration_test, maven_test, bazel_repository_cache_test, java_integration_test, and sandbox-tests entries. Check the linked issue for the Android tests; done means the remaining named remote tests work on RBE without the listed failures.

Written by the indexing model from the issue text.