Remove JUnit-based test in java/lang/invoke from problem list

The underlying race condition code was removed from jtreg.

Running

    make test TEST=test/jdk/java/lang/invoke/MethodHandleProxies

with jtreg 7.3 yields:

Passed: java/lang/invoke/MethodHandleProxies/WithSecurityManagerTest.java
Passed: java/lang/invoke/MethodHandleProxies/BasicTest.java
Passed: java/lang/invoke/MethodHandleProxies/Driver.java
Passed: java/lang/invoke/MethodHandleProxies/WrapperHiddenClassTest.java
Test results: passed: 4



Revert https://bugs.openjdk.org/browse/JDK-8313155 by removing following lines from JDK's ProblemList.txt file:

java/lang/invoke/MethodHandleProxies/BasicTest.java 8312482 linux-all
java/lang/invoke/MethodHandleProxies/WrapperHiddenClassTest.java 8312482 linux-all