Remove erroneous duplicate baseline entry

Due to a bug in Metalava the `VisiblySynchronized` check would report
an erroneous duplicate baseline entry that referenced some internal
implementation detail, e.g. `PsiThisExpression` instead of an actual
API element. Another entry with the same message and correct API
element was also written.

The Metalava bug has been fixed so this change removes the erroneous
entry.

Bug: 311690008
Test: m checkapi
Merged-In: If5550b8cc0a97f02fb7fb1bd949f8e5517007d4c
Change-Id: I79b3c9802e40e74ba7f0c9b102dc201d01ddeab5