RFR: 8274937: Revert the timeout setting for DynamicLoaderConstraintsTest

[Calvin Cheung]

Since JDK-8273612 has been fixed, the increase in the timeout for DynamicLoaderConstraintsTest could be reverted.

Tested with the following VM options on the macosx-x64 platform with fastdebug build with jtreg timeout factor set to 15.

`-Xcomp -XX:+CreateCoredumpOnCrash -ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:+TieredCompilation -XX:-UseCompressedOops`

Test was repeated 20 times with no timeout observed.

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Commit messages:
 - 8274937: Revert the timeout setting for DynamicLoaderConstraintsTest

Changes: https://git.openjdk.java.net/jdk/pull/5961/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5961&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274937
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5961.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5961/head:pull/5961

PR: https://git.openjdk.java.net/jdk/pull/5961