JSR 292 API specification maintenance for JDK 8

Some specification updates to the JSR 292 APIs are requested by the JSR 292 EG for JDK 8.

Items:
- adjust alignment between access checks for CONSTANT_MethodHandle and Lookup.find* API calls
- add wildcard to raw type in parameter to unreflectConstructor
- clarify @CallerSensitive interactions (amended since JDK-7165628)
- clarify wording regarding bytecode behavior and access checking
- other minor edits: use {@code ...} inside <blockquote><pre> tags, etc.

More details:
 
 
- add wildcard to raw type in parameter to unreflectConstructor
The raw type "Constructor" was accidentally included in the original JSR 292 API.
 
 
- clarify wording regarding bytecode behavior and access checking
 
Numerous statements about the accessibility checks and bytecode
behaviors should be clarified. No behavioral changes are needed.
 

This bug can also be used for tracking some additional maintenance items:
- JDK-8025112 spec updates for security manager and caller sensitivity
- JDK-8019417 clarify behavior near arity limits
- JDK-8001109 specify errors that can occur during spreader invocation
- JDK-8001108 clarify that an attempt to use "<init>" as a method name elicits NoSuchMethodException
- JDK-8024599 adjust alignment of class initialiation behavior between method handles and bytecode behavior, for constructors and static members
- JDK-8001110 method handles should have a collectArguments transform, generalizing asCollector