Fix + Run DynamicShapeDetector tests on CI.

[ysiraichi]

DynamicShapeDetector was introduced on #7918. However, it has the following issues:

• The test never run on CI
• Its last commit changed the parameter name of torch_xla.compile() from allowed_traces to num_different_graphs_allowed. However, the tests weren't changes accordingly.
• The tests used the context manager assertRaises(RuntimeError, msg=msg). However, msg was actually supposed to be the expected error.
• From the torch_xla.compile() parameter name to the names used in the implementation, there was no standard. "Traces" and "graphs" were used interchangeably.

This PR fixes the aforementioned issues by:

• Adding the test to the run_tests.sh file
• Replace assertRaises by assertRaisesRegex
• Standardize the name to max_different_graphs everywhere
• Prefer "graphs" to "traces"