(S) 8237750: Load libzip.so only if necessary

[Yumin Qi]

Hi, please review:
bug 8237750: https://bugs.openjdk.java.net/browse/JDK-8237750
webrev: http://cr.openjdk.java.net/~minqi/8237750/webrev-01/
Summary:
   zip library is loaded unconditionally at start up but it is only 
needed when
   1) bootclasspath contains zip or
   2) UseAOT enabled or
   3) VerifySharedArchive turned on or
   4) CDS archives custom loaded classes
    If none of above in java application, it is not necessary to have 
zip library loaded.

   Solution by loading zip library on demand when needed.

Performance for java -Xint version:

Results of " perf stat -r 50 bin/java -Xshare:on 
-XX:SharedArchiveFile=jdk2.jsa -Xint -version "
    1:     59611556    59450206 (-161350)      -----     39.799 40.274 
(  0.475)    ++
    2:     59602708    59425234 (-177474)      -----     40.591 41.183 
(  0.592)    ++
    3:     59579718    59441272 (-138446)      ----      40.777 40.471 ( 
-0.306)      -
    4:     59584882    59410155 (-174727)      -----     40.824 40.233 ( 
-0.591)      --
    5:     59590998    59447252 (-143746)      ----      40.400 40.493 
(  0.093)
    6:     59589523    59441934 (-147589)      ----      40.475 40.064 ( 
-0.411)      --
    7:     59581820    59413612 (-168208)      -----     39.763 40.077 
(  0.314)     +
    8:     59593678    59418738 (-174940)      -----     40.912 39.724 ( 
-1.188)      -----
    9:     59573058    59412554 (-160504)      -----     40.126 40.033 ( 
-0.093)
   10:     59591469    59419291 (-172178)      -----     40.731 40.689 ( 
-0.042)
============================================================
           59589940    59428022 (-161917)      -----     40.438 40.322 ( 
-0.116)
instr delta =      -161917    -0.2717%
time  delta =       -0.116 ms -0.2859%

Tests: hs-tier1-4.
Due to zip library not loaded at default, I removed 'zip' from pmap list 
in test case: *test/hotspot/jtreg/serviceability/sa/ClhsdbPmap.java

**
* Thanks
Yumin