Extend rxm and coll providers to be used with offload provider

[grom72]

Extend rxm and coll providers to work with collective offload providers:

• collective offload provider is given via FI_OFFLOAD_COLL_PROVIDER environment variable
• multinode tests do not fail if a provider does not explicitly support the requested collective operation
• collective offload provider's capabilities override the util coll provider's capabilities

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This change is 

[ldorau]

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[haichangsi]

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[ldorau]

Reviewed 4 of 13 files at r4, 1 of 1 files at r5, 8 of 9 files at r6, 1 of 1 files at r7, all commit messages.
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prov/rxm/src/rxm_ep.c line 393 at r7 (raw file):

	rxm_ep = container_of(ep, struct rxm_ep, util_ep.ep_fid);

	//FI_PEER flag is used to force util_coll context 

Redundant space at the end

Code quote:

t·

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prov/rxm/src/rxm_ep.c line 393 at r7 (raw file):

	rxm_ep = container_of(ep, struct rxm_ep, util_ep.ep_fid);

	//FI_PEER flag is used to force util_coll context 

Use /* */ C-style comment, please

Code quote:

	//FI_PEER flag is used to force util_coll context
	//where fi_join() is called from offload provider

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prov/rxm/src/rxm_ep.c line 402 at r7 (raw file):

		if (ret)
			goto err_util_coll;
		// It is collective offload provider responsibility to store util_coll provider mc

.

Code quote:

// It is collective offload provider responsibility to store util_coll provider mc

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prov/rxm/src/rxm_msg.c line 818 at r7 (raw file):

				   rxm_ep_sar_calc_segs_cnt(rxm_ep, data_len));
	} else {
rndv_send:

An empty line should be used before a label, not after.

Code quote:

	} else {
rndv_send:

		ret = rxm_alloc_rndv_buf(rxm_ep, rxm_conn, context,

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src/fabric.c line 841 at r7 (raw file):

	fi_param_define(NULL, "offload_coll_provider", FI_PARAM_STRING,
			"The name of colective offload provider (default: empty - no provider)");

of a collective offload provider

Code quote:

of colective offload provider

[ldorau]

Reviewed all commit messages.
Reviewable status: all files reviewed, 5 unresolved discussions (waiting on @grom72)